The invention relates to a controllable high performance burner, i.e., a burner which is suitable for the production of high heat outputs of varying degrees. Such a high performance burner has a combustion chamber, with a nozzle extending thereinto, and a mixture preparation device which, among other components, comprises a fuel supply device.
Inasmuch as such high performance burners themsleves produce relatively high temperatures in areas located in front of the combustion chamber, i.e., in the so-called burner headroom which, for instance, may contain the nozzle and the mixture preparation device, any control, and especially stepless control of the performance of such burners, presents difficulties. These difficulties result because such relatively high temperatures tend to affect the temperature-sensitive burner components located therein, thereby jeopardizing a reliably safe operation.
It is a primary objective of the present invention to create a high performance burner which overcomes the above-mentioned drawbacks while enabling its performance to be reliably controlled in a stepless manner. It is a further object to produce such a burner which can be safely operated in a manner which is particularly independent of the temperature level.
In accordance with preferred embodiments of the invention, a high performance burner having a nozzle extending into a combustion chamber, and having a fuel supply device comprising a mixture treatment device, is provided with a mixing chamber for preliminary mixing of fuel and air that is situated upsteam of the burner nozzle. In such a high performance burner, the treatment of the fuel and air (in the form of an emulsion) is facilitated by the premixing chamber, in which the fuel quantity can be varied and can be regulated in an uncomplicated manner to achieve control of the burner performance in a way which, preferably, permits stepless control. The upstream premixing chamber can be located at such an area where it is unaffected by either the temperature in the combustion chamber and/or by other hot gas streams which may occur, e.g., in a process of exhaust gas afterburning. Likewise, the temperature-sensitive burner components are arranged in areas which remain cool to ensure a safe operation.
Advantageously, the premixing in the high performance burner of the invention occurs in the premixing chamber by utilizing auxiliary air which is passed to the premixing chamber from the outside.
Preferably, the fuel quantity which is introduced into the premixing chamber is regulated. To this end, a timed (controlled) solenoid valve, for instance, can be arranged between a fuel pump and the inlet into the premixing chamber. Timing of the solenoid valve permits a reliable control of the fuel quantity entering into the premixing chamber.
The nozzle extending into the combustion chamber diffuses the pretreated fuel-air mixture arriving from the premixing chamber at the inlet side of the combustion chamber of the burner. The mixture is then ignited by a conventional iginition device.
In accordance with another, feature of the invention, the premixing chamber, including the auxiliary air lines and the fuel feed lines, is arranged externally at the burner, in order to perform the premixing occuring in the premixing chamber, independent of the temperatures in the combustion chamber, and/or independent of a possible hot exhaust gas stream.
The auxiliary air delivery device and the fuel supply device, with a fuel pump, and possibly with a fuel regulating device, like a solenoid valve, may constitute a single component with the premixing chamber. Such a component is arranged at an appropriate location, separate from the burner, and by suitable means is in communication with the nozzle extending into the combustion chamber.
The inventive design of the high performance burner not only makes it practical for generating heat by means of a heating device, but the device can also, advantageously, be put into service in connection with the afterburning of exhaust gases. Such afterburning of exhaust gases not only includes regeneration of the soot filter of a combustion engine, particularly that of a Diesel combustion engine, but also comprises the afterburning of exhaust gases in connection with an exhaust gas heat exchanger used for heating purposes. In the latter case, the burner serves to generate heat during those phases when the heat contents of the motor's exhaust gases are insufficient for delivering heat. The auxiliary air introduced in to the premixing chamber not only effects mixing of the varying fuel quantities passed to the premixing chamber, but, moreover, serves to blow out and clean the fuel line and the nozzle during pauses in combustion, and thus, aids in preventing coking of the fuel and, simultaneously, serves to cool the nozzle exposed to the hot exhaust gas stream of the combustion engine.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taking in connection with the accompanying drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention.